THE  STRUCTURE  OF  THE  AZOXY 

GROUP 


BY 


FLOYD  DAVID  HAGER 


THESIS 

FOR  THE 


DEGREE  OF  BACHELOR  OF  SCIENCE 

IN 

CHEMISTRY 


COLLEGE  OF  LIBEKAL  ARTS  AND  SCIENCES 

UNIVERSITY  OF  ILLINOIS 


1922 


I 922 
HI23 


UNIVERSITY  OF  ILLINOIS 


rr  * V 
* 1 


ig2z 


THIS  IS  TO  CERTIFY  THAT  THE  THESIS  PREPARED  UNDER  MY  SUPERVISION  BY 



THE  STRUCTURE  OF  THE  AZOXY  GROUP 

ENTITLED 


IS  APPROVED  BY  ME  AS  FULFILLING  THIS  PART  OF  THE  REQUIREMENTS  FOR  THE 


DEGREE 


OF  _ nsTRY, 


C-CLnJl  Jj  ■ 

Instructor  in  Charge 


Approved 


HEAD  OF  DEPARTMENT  OF 


Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/structureofazoxyOOhage 


ACKNOWLEDGMENT 

To  Dr ,C.S, Marvel, whose  suggestion  formed  the  guiding  idea 
in  this  investigation, whose  help  was  instrumental  in  carry- 
ing out  that  idea, and  whose  encouragement  was  a constant 
source  of  inspiration, the  author  gratefully  expresses 
aChnowledgment  and  appreciation. 


TABLE  OF  C OUT  EXIT  3. 


Page 

Introduction  

Historical  and  Theoretical 

Preparation  of  Nitrogen  Pentoxide 5 

x Reparation  of  Acetylnitrate  6 

Attempted  Nitration  of  Benzilic  Acid  with  Acetylnitrate  • 6 

Preparation  of  Diphenylacetic  acid  7 

nitration  of  Diphenylacetic  acid  with  Acetylnitrate  ...  8 

Preparation  of  Benzhydrol  9 

Action  of  Sydrobromic  acid  on  Benzhydrol  and  Benzhydtrol 

Ethers  

Action  of  Hydrochloric  acid  on  Benzhydrol  and  Nitration 

of  the  Product 

preparation  of  Diphenylbromme thane  and  its  Nitration  ...  14 
1 reparation  of  p,p, diamino-diphenyl-methane  and. Nitration.  15 
Preparation  of  the  ptp,dibrom—  and  ptbrom-pt hydroxy 

derivatives  of  o , o' ,d ini tro-diphenyl-me thane  16 

attempted  Oxidation  of  p,p,aiamino-o, o1 .dinitro-diphenyl- 
me  thane -^g 

Action  of  Chromic  Acid  on  the  Amigo  Hydrochloride  ....  19 

Preparation  of  the  Diacetyl  Derivative  of  the  Amine  ...  19 

Attempted  Oxidation  of  the  Diacetyl  Derivative 3_9 

Summary  

m • • • ••  • • • • ••  • • • 

Bibliography  22 


INTRODUCTION 


Before  the  time  of  the  work  of  A.Angeli  and  his  co-workers, 
there  was  relatively  little  experimental  evidence  for  e stab li shin, 
the  structure  of  the  azoxy  group* The  work  of  Angeli  showed 
rather  conclusively  what  the  structure  is, yet  there  seems  to  be 
some  points  lacking  to  make  the  proof  complete. The  following 
investigation  was  carried  out  in  hope  of  offering  another  and 
perhaps  wholly  conclusive  line  of  proof  of  the  structure  of  the 
azoxy  group. This  proof  consists  of  the  preparation  of  a compound 
of  the  type : j 


the  carbon  atom  to  which  x and  y are  attached  is  asymmetric. On 
the  other  hand,  if  the  structure  is  - , the  compound 


cannot  be  optically  active. 

It  was  realized  at  the  beginning  of  the  investigation  that  if 
a compound  of  type  Ilcould  be  resolved  into  optically  active 
components, the  structure  of  the  azoxy  group  would  be  definitely 
proven  and  Angelas  conclusions  fully  verified. failure  of 
resolution, however , could  mean  that  formula  III  was  corrector 
that  the  racemic  mixture  was  not  separated. 


2. 


HISTORICAL  AND  THEORETICAL. 

As  late  as  1894, Meyer  and  Jacobson(  l) ' stated  that  the  structure- 
of  the  azoxy  group  was  far  from  beiAg  established t and  that  the 
structure  usually  assigned,'^"!)' ~ I, had  no  experimental  proof. 

Other  structures  proposed  were-^W-  II  ,and~  ^36llV ~ III.3riihl(  2 ) f 
basing  his  conclusions  upon  molecular  refraction  data, favored 
II  or  III. His  interpretation  of  data  and  the  assumptions  he 
made  make  his  conclusions  questionable .( 3) ,( 4 ) .Hantzsch  and 

Werner  (5)  proposed  two  stereoisomeric  structures  for  the  group. 


o'*-'* 

W - R 


oN~n 

O 

K-  A/  ' 


In  these  formulas, 0 signifies  half  an  oxygen  atom. They  based 
their  work  on  the  existence  of  the  two  forms  of  p-azoxytoluene 

prepared  by  Janovsky  and  Reimann(6)  and  Lumiere  and  Seyewetz(7). 
Later  work  by  Hantzsch(8)  and  Bamberger  (9)  makes  the  existence 


of  two  forms  of  p-azoxytoluene  doubtful. Bamberger  worked  with 
unsymmetrical  oxyazoxybenzenes^which  he  at  first  thought  existed 
in  two  forms. He  finally  concluded( 10 ) that  in  the  case  of 
o-oxyazoxybenzene  at  least, one  of  the  isomers  was  not  a real 
azoxy  compound. Reissert  (11)  claimed  to  have  prepared  two  forms 
of  azoxybenzene ,but  his  work  could  not  be  duplicated  by  Angeli. 

Lachmann  ( 12) discredits  the  unsymmetrical  structure  of  the 
azoxy  group  on  the  grounds  that: 

(a) . Zinc  ethjl  reacts  vigorously  with  nitrosobenzene  but  not 
with  azoxybenzene, 

( b )  .Azoxybenzene  is  isomeric  with  diphenylnitrosobenzene, 
but  is  much  less  reactive  than  the  latter. 

{ c ) .Pet it ( 13)  points  out  that  the  formation  of  azoxy  compounds 
by  the  oxidation  of  azo  compounds  is  an  exothermic  reaction. 

These  numbers  refer  to  articles  listed  in  the  bibliography. 


3. 


All  the  oxides  of  nitrogen, on  the  other  hand, have  a negative 
heat  of  formation. 

A. Angeli -and  his  co-workers-  (14)  favors  the  unsymmetrical 

struoture-N “ fH e has  prepared  a large  series  of  isomeric 

o 

forms  of  unsymmetrical  azoxy  compounds  by  oxidizing  the  corre- 
sponding azo  compounds  with  30 fo  hydrogen  peroxide. An  example 


will  show  his  general  scheme  of  work: 

p— br omazobenzene , upon  oxidation  with  30/i?  hydrogen  peroxide* 
yields^  and/3p-bromaxoxybenzenes  whose  melting  points  are  73°and 
84° respectively. The  structure  of  the  two  forms  was  established 
by  the  action  of  bromine  and  of  nitric  acid  upon  the  isomers. 


It  was  found  that  the  nucleus  attached  to  the  trivalent  nitrogen 


was  the  one  that  brominated  or  nitrated. 


/S0T- 


( y_  /y  — a/  -<^  ' 13 

■ o 

<3_  n=  a/-c:>ba. 


4-  H A/  0 3 

-f  hi  N °3 


->  <Z> 


A / = ^ 


/3a^ 


4- 


HzO 


0. 


V /Y-0  N = V ^ °' 


Trom  the  preparation  of  a series  of  similar  isomers  and  from  the 


fact  that  he  was  unable  to  prepare,;8yametrical  azoxy  compounds 
that  existed  in  more  than  one  form,Angeli  concluded  that  the  grou.p> 
has  an  unsymmetrical  structure. 

Campbell  (15), using  58$hydrogen  peroxide  and  p-ethpxyazobenzane„ 
found  that  only  one  azoxy  compound  was  formed  and  that  the 
oxidation  was  not  complete. He  suggests  that  in  some  cases  at 
least , Angeli’ s results  are  incorrect  in  that  the  isomers  prepared 
were  probably  mixture s.Mattheus(  16) , using  peracetic  acid  in 

acetic  solutiom  and  p-brom  and  p-ethoxy  azobenzenes  arrived  at 
much  the  same  conclusions  as  Angeli. 

The  work  of  Arndt  (17)  and  of  Arndt  and  Rosenan  (18)  on  the 

preparation  of  cyclic  azoxy  compounds  may  be  interpretated  to 
support  Angeli’ s theoty. These  compounds  can  be  reduced  to  azo 


. 


. 


. . 


. -T  ■ - 


• t 

' 

, , 


. 


4 


and  hydrazo  compounds, and  the  latter  *an  be  oxidized  with  33 5® 
hydrogen  peroxide  to  give  the  original  azoxy  compound,  O-nitro- 


which, by  means  of  3 Sfo  hydrogen  peroxide  and  glacial  acetic  acid. 


Both  isomers  behave  alike  when  reduced. 

Eobinson(l9)  has  shown  that  azoxyveratrole  gives  a mononitro 
compound  while  azoveratrole  gives  a symmetrical  dinitro  compound. 
This  is  in  close  agreement  with  Angelis  theory. 

While  the  work  of  Angeli  is  rather  conclusive  in  proving  the 

structure  of  the  azoxy  group, it  does  not  entirely  close  the 
question. His  inability  to  prepare  symmetrical  azoxy  compounds 

in  two  forms  does  not  exclude  their  existence. Furthermore , as 
Campbell  has  pointed  out(l5),the  purity  of  some  of  the  isomeric 
compounds  is  questionable. In  this  investigation  it  was  planned 
to  try  to  solve  the  problem  by  the  optical  properties  of  a 
certain  type  of  compound.lt  is  possible  the  group  may  exist  in 
different  forms, in  which  case  the  change  of  structure  may  be 
noted  in  the  change  of  optical  properties. 

The  most  promising  compounds  to  use  in  preparing  this  type 
would  be  the  o,o* dinitro  derivatives  of  benzilic  or  diphenyl- 
acetic  acids, or  of  d ipheny lb romme thane.  As  the  experimental 

work  shows, our  hopes  were  not  fulfilled  in  these  respects. At  the 
time  this  investigation  had  to  be  closed, 0,0* dinitro-p,p' - 


C l, ft  diphenylguanidine  may  be  converted  by  boiling  with  sodium 
hydroxide  to  1: 2:4:benztriazine-3-anilino-l-oxide 


t\l  — M H 

,\l  — C-—  N CZ> 


melting  point,197j 


this  can  be  reduced  to  3-anilino-l: 2:4:benztriazine$m.p.l97 ) f 


can  be  oxidized  to  3-anilino-l: 2:4:benztriazine-2-oxide( m.p.  163°) 


* 

- 0 


' 


■ 


• 

• 

1 

• 

» 

p 

• / 

. 

. 

5 


diamino-diphenylme thane  and  its  azoxy  derivative  seemed  to  be 
the  most  promising  compounds  to  use  in  cdntinuing  the  work. 

EXPERIMENTAL. 

PREPARATION  OP  NITROGEN  PENTOXIDE.  Nitrogen  pentoxide  was  pre- 
pared in  a manner  similar  to  the  method  of  Berthelot( 20) . 

Into  a liter  glass  retort  fitted  with  either  a glass  or  asbestos 
stopper , place  85g.  of  phos|>horus  pentoxide. Protect  the  open 
end  of  the  retort  with  a calcium  chloride  tube. Place  the  retort 
in  a freezing  mixture  and  slowly  add  60cc.  of  fuming  nitric  acid 
(sp.gr.  1.52), in  such  a manner  that  it  is  evenly  distributed 
over  the  phosphorus  pentoxide.Do  not  let  the  contents  of  the 
retort  rise  above  0° .The  acid  may  be  added  from  a dropping 
funnel. After  all  the  acid  has  been  added ,-fche  material  in  the 
retort  should  be  very  thick  and  viscous  and  nearly  all  the 

phosphorus  pentoxide  wetted.  Then  place  the  retort  on  a steam 
cone, remove  the  calcium  chloride  tube, and  attach  in  its  place 
a weighed  Erlemmeyer  flask  so  that  the  end  of  the  retort  almost 
reaches  the  bottom  of  the  flask. Asbestos  paper  can  be  used  to 
form  a loose-fitting  stopper  for  the  receiving  flask.Keep  the 
latter  cooled  by  means  of  a freezing  mixture, and  at  the  same 
ti©e  gently  heat  the  retort  on  the  steam  cone  to  distill  off 
the  nitrogen  pentoxide. The  process  is  somewhat  slow  and  generally 
requires  about  two  hours. Do  not  heat  too  vigorously  and  do  not 
allow  any  water  to  enter  either  the  retort  or  the  receiving 
flask.During  the  latter  part  of  the  distillation, some  liquid 
distills  over  and  mixes  with  the  white  crystals  of  nitrogen 
pentoxide  which  form  on  the  sides  of  the  receiving  flask. 


• • . 


. 


. 


6 


This  is  drained  off  as  much  as  possible  and  may  be  used  in  the 
fuming  nitric  acid  of  the  next  run, The  liquid  is  said  to  have 
the  formula  2HaO^,Ha.O.  After  draining  off  the  liquid, the  flask 
and  "wet”  nitrogen  pentoxide  are  weighed  to  determine  the  amount 

of  pentoxide  obtained. The  best  yield  we  got  was  50g.  of  "wet" 
pentoxide  from  85g.  of  phosphorus  pentoxide  and  90g.  of  fuming 
nitric  acid( sp.gr. 1.52) • 

PREPARATION  OF  ACETYLN ITRATE .To  the  nitrogen  pentoxide  is  added 
two  or  three  times  its  weight  of  acetic  anhydride. The  former 
dissolves  immediately  with  very  little  evolution  of  heat. In 
most  cases  it  is  not  necessary  to  isolate  the  acetylnitrate , 
as  it  is  used  in  acetic  anhydride  solution. The  solution  should 
be  kept  in  a cool, dark  place  if  stored  for  any  length  of  time. 
Pictet  and  Zhotinsky  (21)  state  that  acetylnitrate  is  a powerful 
nitrating  agent  and  gives  mainly  ortho-nitrated  products. 

ATTEMPTED  NITRATION  OF  BENZILIC  ACID  WITH  ACETYLNITRATE. 

80g.  of  benzilic  acid  were  dissolved  in  160  cc  of  acetic  anhydride, 
the  solution  cooled  to  -5°  ,and  to  it  added, slowly  and  with  shak- 
ing, acetylnitrate  solution, also  cooled  to  -5"  .The  temperature 
of  the  benzilic  acid  solution  was  not  allowed  to  rise  above  0*  . 

To  each  mol  of  benzilic  acid  was  added, as  nearly  as  could  be 
ascertained, two  mols  of  acetylnitrate. After  the  latter  had 
been  added, the  solution  was  allowed  to  stand  at  Cf  for  half  an 
hour, and  then  poured  into  ten  volumes  of  ice-water. A brownish 
oil  was  obtained, which, after  being  washed  with  water, finally 

solidified. The  solid  product  was  almost  entirely  benzophenone , 
as  shown  by  its  melting  point, 48" ,and  the  melting  point  of 

its  phenylhydrazone ,137*. 54g. , i. e. ,84$  of  the  theory, of  benzo- 
phenone were  isolated. 


■ 

, 


7 


PREPARATION  ON  DIPHENY1ACEIIC  ACID(22). 

Having  seen  that  benzilic  acid  was  oxidized  rather  than  nitrated 
by  acetylnitrafce.it  was  next  thought  desirable  to  attempt 
nitrating  diphenylacetio  acid. The  latter  was  prepared  as  follows? 
Place  in  a liter  flask: 
lOOg.  benzilic  acid 
£5cc  hydr&odie  acid 
25g.  red  phosphorus 
400cc  glacial  acetic  acid. 

Beflux  two  hours, filter .dilute  filtrate  to  1500cc  with  cold  water. 
Diphenylacetio  acid  precipitates , is  filtered  off, and  washed  with 
cold  water.lt  may  be  recrystallized  from  alcohol  or  hot  water, 
yield, 9Bg. ;i.e. ;practically  quantative. 

(Hote:  Benzilic  acid, with  cold, concentrated  sulfuric  acid, 
gives  a red  color ;diphenyl  acetic  acid, under  the  same  conditions, 
gives  no  color. This  test  can  be  applied  to  determine  if  reduction 
is  complete. From  qualitative  tests.it  seems  that  by  this  method 
one  part  of  benzilic  acid  can  be  detected  in  at  least  500  parts 
of  diphenylacetio  acid. The  red  color  with  cold .concentrated 
sulfuric  acid  seems  to  be  given  whenever  there  is  the  following 
grouping  in  the  molecule: 


All  the  following  compounds  were  fou&d  to  give  the  color  except 
the  last  one,  which  gave  a green  color  which  turned  red  after 


a day' s standing. 


c — 


A 


<3)-_  c—  o - H 

Jhl2  C Ot  C*  My 


8. 

NITRATION  OF  DIPHENYLACETIC  ACID  WITH  ACETYLN ITRATE f 
90g.  of  diphenylacetic  acid  were  dissolved  in  150cc  of  acetic 
anhydride  and  nitrated  in  a way  analogous  to  the  method  described 
above  for  benzilio  acid. After  half  an  hour, the  mixture  was 
poured-  into  ten  volumes  of  ice-water.A  reddish  brown, viscous 
oil  resulted. This  product  was  treated  with  boiling  alcohol; 
only  the  first  two  lOOcc  alcoholic  extracts  deposited  appreciable 
amounts  of  solids  upon  cooling. The  residue  was  then  treated 
with  boiling  glacial  acetic  acid. The  first  six  or  eight  iOOcc 
extracts  gave  solids  upon  cooling, but  the  later  ones  gave 
products  of  increasing  gumminess .The  solids  from  the  alcoholic 
and  acetic  acid  extracts  were  combined, dissolved  in  alcohol, 
and  an  attempt  made  to  fractionally  crystallize  the  product. 
Evidentaliy  the  solids  were  a complex  mixture's  each  crop  of 

product  melted  over  a range  different  from  the  others. The  melting 
points  of  the  various  fractions  ranged  from  155°  to  250° .The 
higher  melting  fractions  were  the  more  soluble  in  alcohol. 

The  color  ranged  from  light  yello^in  the  case  of  the  high 
melting  fractions  to  brown  in  the  lower  melting  parts. 

Evidently  a portion  was  alkali-soluble , but  no  satisfactory 
separation  could  be  made  on  this  basis. The  alkaline  solution 
was  opaque  like  some  emulsions, and, upon  acidification, lost  but 
little  of  its  opaqueness  aftd  deposited  a very  gummy  residue. 

This  line  of  investigation  seemed  so  little  promising  that 
it  was  dropped. 

In  nitrating  benzilic  acid  with  acetylnitrate , there  is  much 
oxidation; in  the  case  of  diphenylacetic  acid, there  apparently 
is  some  oxidation.lt  was  then  thought  that  diphenyl  chlor-  or 
brom-methane  would  probably  nitrate  more  readily  and  oxidize  less 


9 


easily.Mphenylbromme  thane , being  a solid, was  chosen, We  first 
tried  to  prepare  it  from  henzhydrol  and  hydrohromic  acid  in 
alcoholic  solution. The  henzhydrol  was  prepared  hy  the  reduction 
of  henzophenone  in  alcoholic  solution  hy  means  of  potassium 
hydroxide  and  zinc  dust. 

PREPARATION  OF  BEN2HYDR0L.  Several  runs  were  made. It  was 
found  that  hy  using  the  same  proportions  thruout,25g.  runs  gave 
much  better  results  than  larger  amounts  ( 100-200g. ) .Unless 
otherwise  noted, the  henzophenone  was  dissolved  in  absolute 
alcohol  to  which  the  potassium  hydroxide  had  been  added, either 
as  a very  concentrated  aqueous  solution, or  as  the  solid  and 
then  dissolved  in  the  alcohol. The  solution  was  then  heated  to 
Boiling  and  the  zinc  dust  added  in  lg.  portions  thru  the  reflux 
condenser. 

Summary  of  the  runs: 

I.  200g.  potassium  hydroxide 

2 litersof  absolute  alcohol 

200g.  of  henzophenone 

250g.  of  zinc  dust. 

The  potassium  hydroxide  was  first  dissolved  in  the  alcohol, 
the  henzophenone  then  added, and  the  solution  brought  to  a boil. 
She  solution  was  stirred  hy  means  of  a mechanical  stirrer 
during  all  the  time  it  was  in  the  reaction  flask.As  soon  as 
boiling  began, the  zinc  dust  was  added. This  process  took  about 
twenty  minutes. The  solution  was  refluxed  for  an  hour , filtered 
while  hot, and  the  residue  washed  twice  with  hot  alcohol. Gare 
had  to  be  taken  that  the  zinc  residue  did  not  become  dry  during 
the  filtering, as  under  these  conditions  it  burned. The  filtrate 


, 


. 


10 


and  washings  were  then  poured  into  five  volumes  of  ice-water. 

The  product  separated  as  a very  gummy , choc olate-brown  mass, 
which  was  purified  by  vacuum  distillation. Boiling  point, 

Yield, 180g,  or  90 

II*  150g.  of  potassium  hydroxide  dissolved  in  50cc  of  water 
1 liter  of  absolute  alcohol 

150g.  of  benzophenone  purified  by  vacuum  distillation 
175g.  of  zinc  dust. 

■fhe  reaction  was  carried  out  as  described  above  .except  that  the 
solution  was  not  stirred. The  product  was  almost  as  brown  as  the 
first  run, and  when  vacuum  distilled, boiled  over  a very  wide 
range.Ihe  following  products  were  identified  in  the  various 
fractions  of  the  distillate:  unchanged  benzophenone ,m.p. 48°; 
benzhydrol,m.p.  68°; diphenylme thane  ,m.p.  26°;and  tetraphenyl ethane  , 
the  1, 1,2, 2, compound, m.p. 209°.  So  complex  was  the  mixture  that 
it  was  thought  not  worth  while  to  make  a complete  separation. 

The  following  series  of  small  runs  were  made  to  determine  the 
effect  of  the  concentration  of  alkali, time  of  boiling, etc. In 
no  case  was  the  reaction  mixture  stirred. The  zinc  dust  was  added 
during  the  course  of  five  minutes. After  refluxing, the  reaction 
mixture  was  poured  into  ice-water  as  described  above. 

III.  53cc  of  an  aqueous  solution  of  potassium  hydroxide ; contained 
24g.  of  the  solid 
EOOcc  of  absolute  alcohol 

25g.  of  purified  benzophenone 
30g.  of  zinc  dust. 

Mixture  refluxed  half  an  hour .Yield, 25g. ,99%,  of  pure  white 
product  that  melted  6^-65° ;the  melting  point  of  pure  benzhydrol 

0 

is  68  .Vv'hen  recrystallized  from  alcohol, the  product  melted  at  68. 


. 


* 


- 

* 

t 

. 


. 


. 

. 


* 


11 


IV.  150cc  of  absolute  alcohol 

53cc  potassium  hydroxide  solution  (24  g.of  solid) 

25g. benzophenone  (not  purified #but  of  good  quality) 

30g.  of  zinc  dust. 

Mixture  refluxed  half  an  hour  andl  treated  as  above .Yield, 25g. 
Quality  similar  to  run  III. 

V.  lOOcc  of  absolute  alcohol 

53cc  of  potassium  hydroxide  solution  ( 24g.  of  solid) 

25g.  of  purified  benzophenone 
30g.  of  zinc  dust. 

Yield, same  as  run  III. 

VI.  150cc  of  95/b  alcohol 

25g.  potassium  hydroxide  in  15cc  of  water 
2 5g.  purified  benzophenone 
30g.  of  zinc  dust. 

fixture  refluxed  for  two  hours, allowed  to  stand  four  days, 
heated  to  boiling, and  treated  as  above .Yield, same  as  run  III. 

VII.  500cc  Of  95 fo  alcohol 

lOOg.  of  potassium  hydroxide  in  40cc  of  water 
94g.  of  purified  benzophenone 
lOOg.  of  zinc  dust. 

Mixture  refluxed  for  forty  minutes, not  stirred, and  treated  as 
outlined  aTnove. Yield, 93g.  of  very  yellowish  product  that  had  to 
be  vacuum  distilled. 

From  these  results, it  seems  as  if  the  size  of  the  run  and  not 
the  concentration  of  the  alkali  of  time  of  refluxing  govern  the 
quality  of  the  product,  -e  have  no  explanation  to  offer  for 
this  behavior. 


12 


ACTION  OB  HYDROBROMIC  ACID  ON  BENZHYDROL  AND  3ENZHYDR0L  ETHERS, 
Attempts  were  made  to  prepare  diphenylbromme  thane  by  the  action 
of  48$  hydrobromic  acid  on  benzhydrol  in  alcoholic  solution( 23) . 
The  first  run  was  made  by  dissolving  lOOg.  of  benzhydrol  in 
500cc  of  95$  alcohol , adding  125cc  of  48/i  hydrobromic  acid, 
refluxing  half  an  hour, and  then  allowing  the  solution  to  stand 
for  ten  hours. A yellojr,oily  product  separated  at  the  bottom  of 
the  mixture. After  repeated  washings  with  cold  water, this  product 

was  found  to  retain  only  traces  of  halogen, It  could  not  be 
solidified, even  by  cooling  to  -15° .When  vacuum  distilled, it 

yielded  a colorless  oil  which  boiled  at  174  /25mm.The  purified 
product  was  halogen  free  and  could  not  be  solidified  at  -15°', 
yield, 96g. 

The  second  run  was  made  similar  to  the  first  except  that 
the  solution  was  allowed  to  stand  at  room  temperature  for 
twelve  hours  and  was  not  refluxed. Two  layers  separated  as  before 
and  the  product  obtained  was  like  that  from  the  first  run. As 
the  boiling  point  of  the  product  did  not  correspond  to  that  of 
benzhydrol  and  as  it  contained  no  halogen, the  compound  was 
neither  benzhydrol  or  diphenylbrommethan4.lt  was  finally  iden- 
tified as  benzhydrol  ethyl  ether  by  its  boiling  point  of  287 6 
at  atmospheric  pressure. 

As  this  ether  could  not  be  used  in  this  work, we  tried  to 
split  it  with  hydrobromic  acid  and  with  hydriodic  acid  in 
hope  of  getting  either  the  halide  oT benzhydrol. 50cc  of  the 

ether  were  refluxed  four  hours  with  200cc  of  48$  hydrobromic 
acid. A solid  product  was  obtained, which, after  recrystallization 
from  alcohol, melted  at  109*  .This  product  contained  no  halogen. 
Evidently  it  was  benzhydrol  ether. Neither  this  ether  nor  the 


* 


. 


- 


13 


benzhydrol  ethyl  ether  could  he  split  with  hydriodic  acid, 
iodine,  and  red  phosphorus. 

We  were  suprised  to  find  ether  formation  in  the  presence  of 
so  much  water, and  made  the  following  runs  to  see  to  what  extent 
this  reaction  would  go: 
lOg.  of  benzhydrol 
20cc  of  48/o  hydrobromie  acid 
36  cc  of  water. 

The  mixture  was  refluxed  half  a n hour.  6 1/4  g.  of  purified 
benzhydrol  ether  were  isolated. Evidently  the  ether  formation 
takes  place  even  in  the  presence  of  large  amounts  of  water. 
lOg.  of  benzhydrol 
20ce.  of  48$  hydrobromie  acid 
50cc  of  benzene. 

The  mixture  was  refluxed  half  an  hour.  Three  grams  of  purified 
benzhydrol  ether  were  isolated  but  no  attempt  was  made  to 
isolate  all  the  product. 

ACTION  OP  HYDROCHLORIC  AC ID  OH  BENHHYDRQ1  AND  NITRATION  OP 
THE  PRODUCT.  One  run  was  made  using  hydrochloric  acid  instead 
of  hydrobromie: 

60g.  of  benzhydrol 
120cc  of  alcohol 

600cc  of  concentrated  hydrochloric  acid 
The  reaction  mixture  was  allowed  to  stand  at  room  temperature 
for  six  hours  and  the  bottom  layer  then  separated  and  vacuum 
distilled.  55g.  of  product  boiling  from  173° to  195° at  25mm. 
was  obtained. This  product  gave  a qualitative  test  for  halogen 

and  solidified  in  a freezing  mixture  but  had  no  definite 


• 

. 

- 

' 

V 


14 


melting  point.lt  was  assumed  to  "be  diphenylchlormethane  and^a-5 
nitrated  with  acetylnitrate  as  described  under  benzilic  acid 
above. A yellojr,oily  product  was  obtained, which, after  a month’s 
standing, deposited  white  crystals. These  were  identified  as 
benzhydrol  ether. This  may  be  taken  to  mean  that  the  original 
product  contained  benzhydrol  ether , benzhydrol  ethyl  ether, 
and  possibly  diphenylchlormethane. After  the  isolation  of 
benzhydrol  ether  from  the  nitration  product, the  yellow, oily 
residue  was  discarded, as  it  was  thought  a dinitro  compound  of 
diphenylchlormethane  would  be  a solid. 

PREPARATION  AND  NITRATION  OP  DIPHENYLBROIMETHANE . Diphenylbr onl- 
ine thane  was  prepared  by  slowly  adding  105g  of  bromine  to  llOg. 
of  diphenylme thane. The  latter  was  put  in  a 500cc  flask  and  heated 
to  110  in  an  oil  bath. The  contents  of  the  flask  were  vigorously 
shaken  after  the  addition  of  each  drop  of  bromine. The  latter 
was  added  from  a dropping  funnel. After  all  the  bromine  had  been 
added, the  reaction  mixture  was  allowed  to  cool  and  was  then 
recrystallized  from  petroleum  ether. A80g.  of  pure  product  were 
isolatedjmore  could  have  been  obtained, but  we  did  not  take  the 
time  to  do  so. The  80g.  of  pure  product  were  nitrated  in  acetic 
anhydride  solution  with  acetylnitrate  solution  at  -5° to  0°, 
as  described  un&er  benzilic  acid. A dark  red, oily  product  was 
obtained  which  was  soluble  in  hot  benzene .No  solid  product, 
however , could  be  crystallized  from  this  solvent. At  this  point 
acetylnitrate  as  a nitrating  agent  was  abandoned. 

PREPARATION  OP  p , p , D I AM  IN  0 -D II  KENY1METEANE . As  the  nitration 
with  acetylnitrate  did  not  give  the  desired  type  of  compound, 

the  preparation  of  o * o’ -dinitro-p,p, diamino-diphenylme thane 


15 


was  carried  out. 

The  first  step  is  the  preparation  of  p, p, diamino-diphenyl- 
methane  from  anhydro-formaldehyd-aniline  .aniline, and  aniline 
hydrochloride ( 25)  . £50cc  of  formalin  ( 40?£>()  was  diluted  to 
four  liters  with  water, and  to  this  solution  was  added, during 
half  an  hour,250cc  of  aniline. The  solution  was  stirred  continually 
hy  a mechanical  stirrer  during  the  adding  of  the  aniline  an®  the 
stirring  continued  at  room  temperature  for  three  hours  afterward. 
The  white, solid  anhydro-formaldehyd-aniline  was  then  filtered 

off .washed  with  water, put  into  a 5-liter  flask, and  to  it  added 
300cc  ©f  aniline  and  400g.  of  aniline  hydrochloride .The  mixture 
was  then  placed  on  a steam  cone  for  36  hours  (later  experiments 
showed  that  24  hours  were  enough) .then  was  treated  with  150g. 
of  sodium  hydroxide  in  500cc  of  water, and  the  mixture  steam 
distilled  until  no  more  aniline  came  over. The  free  amine  that 
remained  was  then  washed  with  hot  water  and  vacuum  distilled. 
Yield, 295g. .boiling  at  255-2657l8-20mm. 

According  to  King ( 26)  .this  product  consists  of  nine  parts  of 

p, p, di am ino-diphenylme thane  and  one  part  of  the  p, o’, isomer. 

uil 

NITRATION  OF  p.p.DIAMINO-DIPHFNYIl/rSTEAlTE^i) The  distilled  amine, 
200g. .was  dissolved  in  three  kilos  of  concentrated  sulfuric 
acid, the  solution  cooled  to  0° .and  to  it  added  90cc  of  fuming 
nitric  acid  (sp.gr. 1.5  ) in  100  cc  of  concentrated  sulfuric 
acid. During  this  process  the  solution  was  stirred  by  means 
of  a mechanical  stirrer  and  the  nitric  acid  added  slowly 
enough  so  that  the  tempfTature  did  not  rise  above  0° .Stirring 
was  continued  two  hours  after  the  addition  of  the  nitric  acid 
and  then  the  reaction  mixture  was  poured  into  ten  liters  of 
ice-water. The  acid  was  then  neutralized  with  sodium  carbonate, 


16 


care  being  taken  that  the  temperature  did  not  rise  above  40°. 

YYhen  a slight  excess  of  carbonate  had  been  added, the  product  was 
filtered  off  «nd  washed  thoroughly  with  water, The  best  way  we 
found  to  purify  the  product  was  to  dissolve  it  in  hot  hydro- 
chloric acid, filter, cool  the  filtrate  to  10ft  or  lower, and  then 
precipitate  the  amine  by  adding  dilute  ammonia  and  at  the  same 
time  stir  very  vigorously.During  the  addition  of  the  ammonia, the 
temperature  should  be  kept  low.  The  precipitated  amine  is  then 
extracted  with  a limited  quantity  of  boiling  alcohol;400cc  per 
lOOg.  of  amine  was  found  quite  satisfactory.  The  insoluble 
portion  is  practically  pure  o, o' -dinitro-p,p, diamino-diphenyl- 
methane, and  melts  at  202°. 

PREPARATION  OP  p,p,DIBR0M-  ML;  p , BBOM-p , HYDROXY  - o,  o'  -DIIIITRO- 
DIPEiliyiiMlilEMES . 50g.  of  the  nitrated  amine  were  dissolved  in 
150cc  of  concentrated  hydrobromic  acid  and  lOOcc  of  water 
and  filtered. The  filtrate  was  cooled  to  O^and  to  it  added 
24g.  of  sodium  nitrite  dissolved  in  fifty  cc  of  water. The 
diazonium  salt  was  then  added, with  stirring, to  a solution 

made  by  boiling  125g.  of  copper  sulphate  and  180g.  of  potassium 
bromide  in  800oc  of  water  with  copper  turnings  until  the 
solution  was  colorless. The  latter  was  also  cooled  to  0° ,and 
during  the  time  of  adding  the  diazonium  solution,  the  temperature 
was  not  allowed  to  rise  above  1*  .Stirring  was  continued  for  half 
an  hour  and  then  the  temperature  allowed  to  rise  to  25°. The 
product  was  then  filtered  off  and  the  excess  cuprous  bromide 

dissolved  out  with  hydrochlorie  acid. The  material  left  after  this 
treatment  was  refluxed  with  400c c of  alcohol  for  half  an  hour 


. 


- 


. 


17 


and  filtered. The  insoluble  portion  consisted  mainly  of  what 
probably  was  p-brom*p-hydroxy-o, o'  dinitro-diphenyl  methane. 
This  compound  was  not  obtained  in  a pure  condition  and  melted 
from  95°  to  100.° 

Analysis:  bromine  determined  By  Volhard  method  after  fusion 
of  the  sample  with  sodium  peroxide. 

0.5109g.  required  14.5  cc  of  O.HO^-N  silver  nitrate  solution, 
making  the  sample  contain  24.1$  bromine. 

C^HqOjN^Br  contains,  22.6 $ bromine. 

The  analysis  of  the  crude  compound  indicated  that  it  contained 
but  little  of  the  dibrom  compound, so  it  was  not  purified. 

By  adding  half  of  its  volume  of  water  to  the  alcoholic 
filtrate  described  above, the  solution  became  milky  and  upon 
standing, deposited  yellowish  crystals, which, according  to  their 
bromine  content, were  mainly  the  dibrom  compound. Only  two  grams 
of  these  crystals  were  isolated; these  we  know  were  not  pure 
and  melted  from  120°to  125! 

Analysis:  0.5676g.  required  24.7cc  of  0.164  N silver  nitrate 

solution, i.e. ,36.1$  bromine. 

C;3H$0iKJlBr!l  is  38.4$  bromine. 

Another  run  was  made  using  a suspension  of  cuproub  bromide 
instead  of  the  reduced  copper  solution  described  in  the  notes 
on  the  first  run. The  cuprous  bromide  was  prepared  by  passing 
sulfur  dioxide  thru  a solution  of  copper  sulphate  and  potassium 
bromide, then  filtering  and  washing  the  product. In  this  run  no 
dibrom  compound  could  be  isolated. Because  of  the  poor  yields, 
no  more  attempts  were  made  to  prepare  the  dibrom  compound. 
Attempts  were  made  to  reduce  the  impure  monobrom  compound 


18 


to  the  azo  or  azoxy  derivative  by  means  of  potassium  hydroxide 
and  zinc  dust  in  alcoholic  solution, by  means  of  sodium  and 
alcohol,  and  by  means  of  sodium  methylate. In  all  cases  amorphous, 
reddish-brown  products  that  did  not  melt  but  which  carbonized 
from  £00*  to  300° were  obtained. The  impure  dibrom  compound  was 
treated  with  sodium  in  alcoholic  solution  but  the  product  ■ 
obtained  was  somewhat  like  that  obtained  from  the  monobrom 
compound, and  could  not  be  purified. 

Eing(26(  describes  a method  of  reducing  the  nitrated  amine 
to  the  corresponding  azoxy  compound  by  means  of  sodium  sulfide in 
alcoholic  solution. We  intended  to  try  this  method  of  preparing 
an  azoxy  derivative  after  oxidizing  the  amine  to  a ketone  or 
secondary  alcohol: 


ATTEMPTED  OXIDATION  OF  TEE  AMINE  WITH  LEAD  PEROXIDE.  We  tried 
to  oxidize  the  amine  to  the  alcohol  by  the  method  of  Mbhlau 
and  Heintze  (2$), using  lead  peroxide. The  dihydrochloride  of 
the  amine  we  obtained  free  from  excess  hydrochloric  acid  by 
dissolving  the  amine  in  hot , concentrated  hydrochloric  acid, 
filtering, allowing  to  cool, and  filtering  off  the  hydrochloride 
which  separated  out. This  hydrochloride  was  then  dissolved  as 
much  as  possible  in  hot  water, allowed  to  cool, filtered , and  the 
amount  of  amine  determined  in  lOOcc  of  the  filtrate  by  precipi- 
tating it  with  ammonia. In  the  solution  used, there  ware  2 l/4g. 

per  160cc  of  solution. To  680cc  of  this  solution  were  added 
6cc  of  glacial  acetic  acid, cooled  to  0°,and  treated  with  12g. 
of  finely  powdered  lead  peroxide. The  solution  was  shaken 


. 


, 


- 


9 


V 


. 


• 

. 

19. 

vigorously  for  five  minutes, and  then  divided  into  two  parts. 

To  the  first  part  was  added  8 g.  of  crystalline  sodium  sulphate 
in  solution, and  the  reaction  mixture  filtered. The  amine  in  the 
filtrate  was  precipitated  with  ammonia, washed, and  dried. A mixed 
melting  point  showed  that  it  had  not  been  changed. The  other 
portion  of  the  solution  was  allowed  to  stand  with  the  peroxide 
for  half  an  hour, was  occasionally  shaken, and  then  treated  ad 
the  first  portion. In  this  case  too,  the  amine  was  found  to  be 
unchanged. 

ACTION  OF  CHROMIC  ACID  TOON  THE  AMINE  HYDROCHLORIDE.  A strongly 
acid  solution  of  the  amine  hydrochloride  was  treated, when  warm, 
with  enough  chromic  acid  to  oxidize  it  to  the  keto  compound. 

An  insoluble, reddish-brown  precipitate  formed  when  the  chromic 
acid  was  added. This  precipitate  contained  chromium, and  may  be 
a chromate  salt  of  the  amine, but  was  not  further  investigated. 
PREPARATION  OF  THE  DIACETYL  DERIVATIVE  OF  p,p,DIAMINQ-o, o' - 
DINITRO-DIPHENYIMETHANE.  50g.  of  the  free  amine  were  treated  with 
100c c of  acetic  anhydride. After  the  reaction  mixture  had 
cooled, the  semisolid  mass  was  poured  into  ice-water  and  washed 
free  from  acid. The  product, when  recrystallized  from  alcohol, 
melted  at  2386  ,and  from  its  method  of  preparation, was  thought 
to  be  the  diacetyl  derivative  of  the  amine.lt  is  fairly  soluble 
in  hot  alcohol  and  very  soluble  in  glacial  acetic  acid. When 
saponified  with  2 5fo  sulfuric  acid, it  yields  the  original  amine. 
ATTEMPTED  OXIDATION  OF  THE  DIACSTYL  DERIVATIVE.  Attempts  were 
made  to  oxidize  the  diacetyl  derivative  in  boiling  acetic  acid 
solution  by  means  of  sodium  dichromate , of  chromic  acid, and 
of  potassium  permanganate  in  acetic  acid  solution. In  each  case 


20 


about  110 yo  of  the  theoretical  amount  of  oxidizing  agent  necessary 
to  oxidize  the  amine  to  the  keto  compound 


were  used* The  oxidizing  agents  were  reduced, but  when  the 
product  was  recrystallized  from  alcohol, in  every  case  it  was 
found  to  be  unchanged. 

Time  did  not  permit  further  experimental  work, but  at  the  end 
of  the  investigation  it  seemed  that  the  following  lines  of 
attack  may  yield  the  desired  results*. 

I.  It  may  be  possible  to  substitute  one  of  the  hydrogens  of 
the  aliphatic  carban  with  bromine  and  then  reduce  to  the 
corresponding  azoxy  derivative. 

II.  The  azoxy  derivative  may  first  be  prepared  and  then  the 
aliphatic  carbon  atomm  be  oxidized, or  brominated. 


. 

. 


* 


, 

. 


21. 

NUMMARY. 

* . Acetyl  m trace  has  a o wrongly  Gx.i.ui exxect  upon  o enorlxw 

wwixj  vOIl . Ji  ui.*g  1 t uaCcI iiX  j wO  0© i'i & O vii w n One  . 

l.lTc  definite  products  o oula  he  isolated  from  the  nitration  ox 

tAj.  x a©  w w 1 O d>OX  d ullu  O.  xl  4vnwi.y^cA  u hun  w • a caw  j J a - - w a c 

o.Benshydr  ol  © ! «jr  and  benshydrol  ethyl  ether  are  readily 
formed  from  the  corresponding  alcohols  in  the  presence  of 
hy  dr  chromic  acid. 

4.  p,p,diamino-c,o’ ,dinitr  o-diphenylme thane  was  prepared  and 
unsuccessful  attempts  were  made  to  prepare  the  cor ..espondirg 
secondary  alcohol  and  ke to  derivatives. 

5*p,p ,dibrom-  and  p, hr om-p, hydroxy  deri  ati  s of  o,c ’ , o- 

diphenylme thane  were  prepared  in  an  impure  cc  rliticn  and 
ati  mpts  made  to  reduce  these  compounds  to  the  correspondi  g 
a so  or  usexy  derivatives. 

6. The  diacetyl  derivative  of  p,p, diamimo-o, o' , dinit ro-diphenyl- 
me thane  was  prepared  and  attempts  made  to  oxidise  it  tc  the 
koto  derivative. 

T • Lack  of  time  prevented  the  preparation  of  the  type  of 
compound  desired  in  demonstrating  the  structure  of  the  -:y 

group . 

8 .A  color  reaction  was  discovered  which  may  he  specific  for 


the  grouping: 


O-f 


o 


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2.  Brfihl: Per. XXXI, 1361, ( 1895);  XXXI T ,122,(1629) 

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5.  Hants  h erner:Ber.  XXIII, 1345, (1890) 

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ii 


* 


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